A facebook insider decided that facebook wasn't worth keeping his money in prior to the IPO. That is highlightable..

He converted a $500,000 investment into more than $1,000,000,000, which is at least 200,000% ROI. Would you recommend against diversification at this point? Do you provide financial advisory services by any chance?

I am positive he is doing diversification but not with facebook as part of his portfolio; as he sold pretty much all of his facebook stock. So once again. Facebook insider chooses to sell most of his stock prior to IPO, and prior to first quarter results. Very highlightable..

he sold 80% of his stock IIRC.

By the reports, he made 800x on his investment. He's held on for a while already.

Should Warren Buffet sell on his total investment? I mean he's got a return of 10000000x, and he's been in it for a really really long time..

A) he has sold a good portion of it. B) Berkshire Hathaway is a holding company. It is diversified already. So there is much less of a need to sell it.

So you're saying Berkshire Hathaway is much better setup as a long term business than Facebook; therefore a better investment. I don't disagree at all.

No, being diversified doesn't instantly make you a better business. But it does make you a safer investment.